Re: [PATCH v4 6/8] perf/tools: Enhance JSON/metric infrastructure to handle "?"

Jiri Olsa
2020-03-12T10:53:00Z

On Mon, Mar 09, 2020 at 11:55:50AM +0530, Kajol Jain wrote:

SNIP

> diff --git a/tools/perf/util/expr.h b/tools/perf/util/expr.h
> index 9377538f4097..d17664e628db 100644
> --- a/tools/perf/util/expr.h
> +++ b/tools/perf/util/expr.h
> @@ -15,6 +15,7 @@ struct parse_ctx {
> struct parse_id ids[MAX_PARSE_ID];
> };
>
> +int expr__runtimeparam;
> void expr__ctx_init(struct parse_ctx *ctx);
> void expr__add_id(struct parse_ctx *ctx, const char *id, double val);
> int expr__parse(double *final_val, struct parse_ctx *ctx, const char *expr);
> diff --git a/tools/perf/util/expr.l b/tools/perf/util/expr.l
> index 1928f2a3dddc..ec4b00671f67 100644
> --- a/tools/perf/util/expr.l
> +++ b/tools/perf/util/expr.l
> @@ -45,6 +45,21 @@ static char *normalize(char *str)
> *dst++ = '/';
> else if (*str == '\\')
> *dst++ = *++str;
> + else if (*str == '?') {
> +
> + int size = snprintf(NULL, 0, "%d", expr__runtimeparam);
> + char * paramval = (char *)malloc(size);

can't we agree that any reasonable number in here
wouldn't cross 20 bytes in string or so and use
buffer for that instead of that malloc exercise?

thanks,
jirka

> + int i = 0;
> +
> + if(!paramval)
> + *dst++ = '0';
> + else {
> + sprintf(paramval, "%d", expr__runtimeparam);
> + while(i < size)
> + *dst++ = paramval[i++];
> + free(paramval);
> + }
> + }

SNIP